First of all read this thread by UCrewX5 which is where you can download the update image and also read through how to do it.
Read this thread
I have done this post for UK X5 owers to show that the upgrade also works on the UK system. Even though we were told it did, I was still a little worried about doing it, not wanting to get different measurements and voices etc.
So, I followed the instructions and booted the system up by turning the ignition on (at this point I also turned OFF the auto headlights and rear DVD system to stop excessive battery drain).
I then removed the navigation CD and inserted the upgrade CD, got this picture. please excuse the very poor quality, it was actually dark when I did all this as I couldnt wait for daylight.
Then when the disk had initialised i got a little worried as the screen went blank for about 15 seconds.
Finally I got the message I was waiting for.
The next screen confirmed that I was getting the UK upgrade and that all looked ok.
Finally the install finished and the disk was ejected.
I clicked OK, the system re booted and I got my new sparkling software.
Hope this is of help to somebody.